Charged species learning hub
Polyatomic Ion Lewis Structures
Compare electron counts, charge adjustments, resonance and geometry for commonly studied ions. Open each reviewed guide for the complete electron-placement discussion.
Reviewed polyatomic ion examples
| Ion | Valence electrons | Main lesson | Guide |
|---|---|---|---|
| NO3− | 24 | Three equivalent N–O positions in the resonance hybrid | Nitrate guide |
| NO2− | 18 | Two resonance contributors and a bent shape | Nitrite guide |
| CO32− | 24 | Charge is delocalized across three oxygen atoms | Carbonate guide |
| SO42− | 32 | Contributor conventions vary; verify formal charges | Sulfate guide |
| PO43− | 32 | Tetrahedral connectivity with distributed negative charge | Phosphate guide |
| ClO4− | 32 | Four equivalent oxygen positions in the resonance hybrid | Perchlorate guide |
| HCO3− | 24 | The O–H bond fixes one oxygen position | Bicarbonate guide |
| NH4+ | 8 | Four N–H bonds and no nitrogen lone pair | Ammonium guide |